Delay arming device



July 6, 1954 J. MEISTER DELAY ARMING DEVICE Filed Nov. 28, 1951 Patented July 6, 1954 DELAY ARMING DEVICE Jack Meister, Bronx, N. Y., assignor to the United States of America as represented by the Secretary of the Army Application November 28, 1951, Serial No. 258,734

(Granted under Title 35, U. S. Code (1952),

sec. 266) '10 Claims.

The invention described in the specification and claims may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon. This invention relates to a delay arming device for a fuse or booster Delay arming devices in fuses and boosters for rotating or spimstabilized projectiles of the type such as is common in artillery ammunition are desirable fromthe standpoint of maintaining the fuse in safe and-unarmed position until the projectile has left the bore of the weapon, in order to protect operating personnel from premature explosions. Fuses using the expedient of a ball arming rotor to supply the necessary delay, in arming are well known in, the art. However, priorart devices,though effective to maintain the fuse safe while the projectile is traversing the gun. bore, have fallen short in providing suihcient time to enable the projectile to clear forward battery positions, or to maintain the projectile fuse in safecondition until the projectile has arrived in the vicinity of the aimed-for target.

Soalso in spin-stabilized rockets it' is often desirable that considerable time elapses before the rocket becomes fullyarmed to, explode on impact, in orderto insure that the projectile has traveled to a location where theblast propagation can no longer affect friendly personnel. ,7 a

Itis therefore a primary object of this invention to provide'a centrifugal force responsive delay arming device whichwill permit a longer time to elapse while a projectile is in flight beforethe fuse becomes fully armed... v I

. It is also an objectof this invention to provide a centrifugal force responsive delay arming device incorporating more than one ball arming rotor to. insure a longer delay in fuse arming.

It is also a further object of this invention to provide acentrifugal force responsive delay arm-' ing device including more than one rotor wherein a preceding rotor acts as a locking means, to retain a successive contiguousrotor inunarmed position until the first rotor hasitself moved into armed position. a

It is also a further additional object of this in vention to provide, means to lock the first rotor in unarmed position and responsive to centrifugal forces set up by the rotating projectile to unlock the rotor so that it may precess into armed position.

With these and other objects in view which will become apparent as the following specificapanying drawing wherein: Y

Figure 1 is a longitudinal section of the forward portion of a projectile incorporating the device of the present invention with the delay arming mechanism in unarmed position.

Figure 2 is a section showing the delay arming mechanism of Figure 1 in fully armed position.

Figure 3 is a transverse section taken on line 33 of Figure 1 showing the centrifugal force responsive means for locking the forward rotor in unarmed position.

Figure 4 is a section taken on line 4-4 of Figure 2.

Figure 5 is a view in detail of the forward rotor for receiving the detonating capsule.

Referring more particularly to Figure l, the 7 device comprises a main body portion I of the shell peripherally recessed as at 2 to receive the nose 3 of the projectile to complete the forward ogive. The main body portion comprises an axially stepped bore 4 a portion of which is internally threaded as at 4:1. to screw-threadedly receive the outer forward wall 5 of a container for accommodating a booster charge 6 in the well known manner. The forward wall of booster container 5 is internally threaded asat 7 to screw-threaded- 1y receive the main housing 8 of the delay arming device, the forward portion of which extends forwardly into a reduced portion of stepped axial bore 4. The usual explosive or incendiary charge 9 is received in the rearward enlarged portion ofaxial bore 4 as plainly seen in Figure 1.

Referring now to Figures 1 and 2, there is formed in main housing 8 a forward axial bore It] communicating rearwardly with a larger axial counterbore I I Which in turn communicates with anweven larger axial counterbore I2 internally threaded as at I3. An annular disc shapedmember I4 is received in the forward portion of counterbore I2 to abut theshoulder Ila, formed by counterbores II and I2 and making a comparatively tight fit with the walls of counterbore I2. A plug or. annulus I5 having an external screw thread [6 to screw into threads I3 is received in counterbore I2 with a forward flat surface I! abutting the rear face of disc l4. An axial flash passage I8 is formed in the rearward portion of plug I5 to communicate rearwardly with the booster container -Sand forwardly with an axial counterbore I9 in plug I5 ofdiameter approximately equal to the diameter of counterbore II.

Received respectively in counterbores II and I9 are substantially spheroidal arming ball rotors 20 and 2| with contiguous surfaces resting respectively in opposed spherical seats 22 and 23 formed in the front and rear faces of disc I4. The opposed concave surfaces of disc l4 forming spherical seats 22 and 23 are truncated centrally to form an aperture 24 to permit the arming ball rotors to face upon and touch each other at this point. Arming ball rotor has a central cylindrical portion cut out to provide a diametral or axial bore 25 to receive a detonating capsule 26 containing an explosive of considerably less specific gravity than the metal rotor. The peripheral surface of the arming ball rotor 20 is dished out as at 21 in axial alinement withthe rear term,- inus of bore 25 to form a concavity for a purpose to be later described. The concavity 21 and bore 25 are separated by an abutment or shoulder 28 made integral with rotor '20 and having an axial bore 29 of smaller diameter than,bor e=,25 Shoulder 28 serves as a stop for the bottom of detonating capsule 26.

The peripheral surface of rearwardly located arming ball 2|, received in counterbore I9, is dished out to form a plurality of concavities 30, so that a cross-section as seen in Figures '1 and :2 presents a substantially crescent-shaped configuration but with the portions 3| represented by the truncated points of the crescent formed as convex-spherical bearing surfaces to contact, when rotating, the walls of bore l9, seat '23, and concavity 27 in ball rotor 20, as later to be described. Ball rotor 2| is provided with a cylindrical axial or diametral bore 32 to form a flash passage extending between the periphery of two of the convex-bearing surfaces 3|, and with a diameter approximately the same as bore 29, to aline therewith when the fuseis armed.

The detent means to prevent the forward arming ball rotor from rotating until released by centrifugal force comprises a peripheral recess or groove 33, formed in main housing 8, communicating with a plurality of radial bores 34 in each of which is received a detent pin 35 with the innermost end of each pin resting in drilled cavities 36 formed in rotor 20 when the fuse is unarmed (seeFigure 3). The pins 35 are biased into ball locking position by a C-type spring 31 which is circumferentia'lly received in groove 33. The spring forms almost a complete circle and has free ends 38abutting a stop 39' extending into groove 33 to prevent the springfrom turning. ternatively it is to be understood that insteadof G-type spring 33, each pin may beindividually biased into ball locking position by separate compression springs.

The firing pin may or may not be'used to provide additional locking means for the forward rotor. In the illustrated embodiment and as clearly seen in Figure 1, the firing pin is also used to lock the forward rotor in unarmed'position, however since this expedient forms no part of the present invention it will only briefly be described. The firing pin 40 is received in axial bore l0 and has a rearwardly directed point 4| received in a drilled shallow hole 42 in the peripheral surface of the rotor, when the fuse is unarmed. Centrifugal force responsive means (not shown) maintain the pin in this position, I

however when the projectile is in flight the pin will be released to creep forwardly and out of hole 42 so that the rotor 20 can precess into armed position.

Op cration Figure 1 illustrates the delay arming device in unarmed position. Under static conditions spring 33 biases detent pins 35 into drilled cavities 36 to hold ball rotor 20 in unarmed position.

4 As explained above, firing pin 40 is pressed rearwardly into hole 42 to accomplish the same purpose. In this position the axis of cylindrical detonator 26 lies crosswise of the longitudinal axis of the fuse. So also in this-position, the spherical surface of rotor '20 sliclably engages one of the dished out cavities 30 in rotor 2|, a portion of this surface also slidably engaging the forward spherical seat 22 in disc I4. It can readily be seen that so long as this engagement obtains ball rotor 2| cannot. precess in response to centrifugal action until .the rotor 20 has moved into armed. position. In the unarmed position flash passage .32 in rotor 2| also lies crosswise of the longitudinal axis of the fuse, but is turned through an angle of approximately from the axis of rotor 20.

When the projectile is fired it commences to spin because of the gun rifling or other means employed for that purpose, however, while, the projectile is traversing the gun bore, setback forces hold the detent pins ,35 and firing pin point 4| in their respective holes to maintain the fuse unarmed. As soon as the projectile leaves. the muzzle of the gun and setback forces cease, detent pins 35 move out against the bias of spring 31' under the action of centrifugal forces and firing pin too is released. so that it may creep forward under the influence of linear acceleration to release the ball rotor 20; Centrifugal forces cause rotor 20' to precess until its axis coincides with the longitudinal axis of the projectile. When this occurs concavity 21 completes, with spherical seat 23 in disc M, a spherical cavity which is engaged by a bearing surface 30 of rotor 2| thereby releasing rotor 2| so that it can now precess under the influence of centrifugal force until its axis coincides with the longitudinal axis of the fuse to attain a fully armed position for the entire arming device. Upon. impact, therefore, pin '40 is ,driven'rearwardly to strike detonator capsule ,26 and the explosion proceeds through bore 29 into flashpassage 32" of rotor 2|, then into flash passage I8, to ignite the explosive in the booster and finally the charge in the shell. It. is to be noted at this time that ball rotors 2B and 2| are arranged to precess in opposed di-'- rections so that the frictional forces due toretation and precession will assist. one another.

It is readily apparent that a plurality. of interlocking rotors in excess of the two shown may also .be used, and also thatthe arrangement of detonating capsule and flash passage may bejre versed in the rotors. Additionally other means than the illustrated firing pin may be used to initiate ignition upon impact orv otherwise.

Other modifications and. alterations will: be, apparent to one skilled in the art, and it isobvious that the same may be made without. departing from the spirit and scope of the invention as defined in the following claims.

I claim:

1. In a point detonating fuse for a rotating projectile, a body, a rearwardly directed firing pin located forwardly in said body, a first spheroidal rotor having a diametral detonator located rearwardly of said firing pin in said body, a secondspheroidal rotor having a diametral flash passage located in said body rearwardly of and axially alined with said first rotor and said firing pin, the axes of said flash passage and said detonator lying crosswise of the longitudinal axis of said body when the fuse is unarmed, means to lock said first rotor in unarmed position, and means including a spherical concavity for-med in the peripheral surface of said second rotor engaging the spherical surface of said first rotor to lock said second rotor in unarmed position.

2. The combination in claim 1 wherein said means to lock said first rotor in unarmed position comprises a plurality of detent pins received in radial passages in said body and extending into holes in said first rotor, and resilient means to bias said pins inwardly.

3. The combination in claim 2 whereby said detent pins are outwardly movable under influence of centrifugal force to release said first rotor for precession into armed position.

4. The combination in claim 1 wherein said detonator and said flash passage are out of axial alinement with each other and with said firing pin when said fuse is unarmed.

5. In a fuse for a spin-stabilized projectile a first centrifugal spheroidal rotor comprising a diametral detonator, a second substantially spheroidal centrifugal rotor axially alined with said first rotor and having a diametral flash passage, a plurality of resiliently inwardly pressed radial detent pins received in holes in said first rotor to lock said first rotor in unarmed position, said detent pins moving outwardly in response to centrifugal force to release said rotor for precession into armed position, said second rotor having a spherical concavity in its periphery to engage the spherical surface of said first rotor when said first and second rotors are in unarmed position to lock said second rotor in unarmed position, said first rotor having a spherical concavity in its periphery to engage a spherical surface of said second rotor when said first rotor has precessed to armed position, whereby centrifugal force permits said second rotor to precess into armed position.

6. In a point detonating fuse for a rotating projectile, an elongated body symmetrical about a longitudinal axis, a rearwardly directed firing pin located in a forward bore in said body, a first arming ball rotor located in said body rearwardly of said firing pin and having a diametral bore with its axis lying crosswise of the longitudinal axis of said body when said fuse is unarmed, a detonator received in said diametral bore, detent means in said body locking said first arming ball rotor in unarmed position, resilient means to bias said detent means into ball looking position, a second arming ball rotor located in said body rearwardly of said first ball rotor and having a diametral flash passage with axis lying cross said longitudinal axis when said rotor is in unarmed position, said second ball rotor having a spherical cavity in its periphery to engage the spherical surface of said first rotor in unarmed position to lock said second rotor in unarmed position.

7. The combination of claim 6 wherein said detent means to lock said first rotor in unarmed position comprises a plurality of detent pins received in radial bores formed in said body and biased to extend into holes formed in the periph-v ery of said first rotor.

8. The combination in claim 7 wherein said detent pins are outwardly movable in response to centrifugal force to release said first rotor for precession into armed position, said first rotor having a cavity to engage a spherical portion of said second rotor when said first rotor is in armed position, whereby said second rotor is released so that centrifugal force processes said second rotor into armed position.

9. In a centrifugally-armed fuse, a body having a flash passage therein, first and second balls mounted for rotation only in contiguous relation in said passage, each ball having a diametral bore determining an axis of maximum moment of inertia, said first ball having one end of its bore enlarged in the form of a spherical concavity symmetrical therewith and within which said second ball may turn only when the bore of said first ball is aligned with said passage, said second ball having a spherical concavity circumferentially offset from its said axis and in which fits a contiguous portion of said first ball to thereby maintain said second ball with its bore out of alignment with said flash passage and said fuse unarmed.

10. In a centrifugally-armed fuse, a body having a flash passage therein, first and second balls mounted for rotation only in contiguous relation in said passage, each ball having a diametral bore determining an axis of maximum moment of inertia, said first ball having one end of its bore enlarged in the form of a spherical concavity symmetrical therewith and within which said second ball may turn only when the bore of said first ball is aligned with said passage, said second ball having a spherical concavity circumferentially offset from its said axis and in which fits a contiguous portion of said first ball to thereby maintain said second ball with its bore out of alignment with said flash passage and said fuse unarmed, and centrifugally released means securing said first ball with its bore out of alignment with said passage.

References Cited in the file of this patent UNITED STATES PATENTS Date 

